Definitely wiggle-room. A rough guess might be about 1/4 inch. What I do is use a folded paper towel to reduce rattle. (Fold into a square, lay it on the top, then push it down in with the canister)
On the left is the 1L with two 110g canisters, Toaks spoon(not folding), Pocket Rocket 2, and a mini Bic.
On the right is the 700mL with one canister, Toaks folding spoon, Snow Peak LiteMax, and a mini Bic.
The lids screw onto both.
The 1L requires a little giggle to get the lid to slip down around the burner but it fits.